Fulvene purification

ABSTRACT

The present invention provides a method of removing undesired isomers, including substituted cyclopentadiene regioisomers, from the desired fulvene in a crude fulvene composition by selectively reacting the undesired isomers with pyrrolidine and 4-(N,N-dimethylamino)benzaldehyde. This reaction converts the undesired substituted cyclopentadienes into fulvene-type compounds that is readily separated from the desired fulvene.

TECHNICAL FIELD OF THE INVENTION

This invention relates to the field of organic synthesis, includingchemistry that is useful for the preparation and purification offulvenes, and use of the purified fulvenes in the synthesis ofbis(cyclopentadienyl)alkanes and ansa-metallocenes.

BACKGROUND OF THE INVENTION

Metallocenes constitute useful catalysts for olefin polymerization whencombined with a cocatalyst such as an aluminoxane. It is generallyaccepted that the properties of the polymers formed using such catalystcombinations are determined in large part by the structural nature ofthe metallocene, including the steric and electronic features impartedto the complex by its cyclopentadienyl ligands. Therefore, there is acontinuing need to develop improved methods for preparing metallocenesand their precursor ligands that allow for a range of diversesubstituents to be incorporated into the ligand structure. There is alsoa need for improved methods for preparing metallocenes that provide thedesired compounds as well as their precursor ligands in higher yieldand/or greater purity.

One step in the preparation of certain metallocenes is the isolation ofan intermediate fulvene. Fulvenes have the general formula C₄R″₄C═CRR′and the following structure:

wherein R, R′, and R″ are generally and independently hydrocarbyl orhydrogen. As precursors to cyclopentadienyl ligands and metallocenecompounds, fulvenes can provide a means for integrating a range ofsubstituents into the metallocene structure. One aspect of this utilitycan be seen from the reaction of fulvenes with anionic cyclopentadienyl(Cp), indenyl (Ind), or fluorenyl (Flu) reagents as illustrated inScheme 1, because the resulting products can be used as ligandprecursors to form bridged or ansa-metallocenes. Ansa-metallocenecatalysts are useful in olefin polymerizations in part because of theimpact the tailored ligand set can have on the properties of theresulting polymer.

Therefore, it is of interest to develop new methods to prepare fulvenesthat may provide these ligands in higher yields, greater selectively,and/or greater purity. It is also of interest to develop new methods toprepare ansa-metallocenes based on new fulvene synthetic methods.

SUMMARY OF THE INVENTION

This invention encompasses methods for purifying a fulvene compositionto afford a substantially pure fulvene, which can then be employed inthe synthesis of bis(η⁵-cycloalkadienyl)-type ligands and metallocenecomplexes. This purification process can be useful when the fulvene isprepared by any method, including methods that are considered relativelyselective. The substantially pure, isolated fulvenes are particularlyutilitarian in preparing “tightly-bridged” ansa-metallocenes, meaningthat the two η⁵-cycloalkadienyl-type ligands of the metallocene areconnected by a bridging group wherein the shortest link of the bridginggroup between the η⁵-cycloalkadienyl-type ligands is a single atom.

Methods of preparing fulvenes having the general formula C₄R″₄C═CRR′(1), wherein R, R′, and R″ are generally and independently hydrocarbylor hydrogen, include the reaction of a ketone O═CRR′ with an anioniccyclopentadienyl reagent such as Li[C₅R″₄H] or Na[C₅R″₄H], typically inalcoholic solvents, or in ethereal solvents followed by reaction with aproton source. This synthetic procedure often generates varying amountsof undesired regioisomers including substituted cyclopentadienes, alongwith the desired fulvene, thereby rendering isolation, purification, andsubsequent use of the desired fulvene isomer tedious and difficult. Whenmagnesium cyclopentadienyl reagents such as Grignard reagents areemployed in this reaction, the desired fulvene compound can be formed inlarge excess over the undesired isomer, however isomer formation stilloccurs under some conditions. This magnesium cyclopentadienyl method isdisclosed in U.S. Patent Application Publication No. 2005/0288524, whichis incorporated herein by reference in its entirety. Because startingwith very pure fulvene greatly simplifies the subsequent fulvenereaction with anionic cyclopentadienyl (Cp), indenyl (Ind), or fluorenyl(Flu) reagents as illustrated in Scheme 1, any procedure which allowspurification of the fulvene, even from Grignard reactions describedabove, are of interest.

Thus, in one aspect, the present invention provides a method of removingundesired isomers, including substituted cyclopentadiene regioisomers,from the desired fulvene in a crude fulvene composition by selectivelyreacting the undesired isomers with pyrrolidine and4-(N,N-dimethylamino)benzaldehyde. This reaction converts the undesiredsubstituted cyclopentadienes into a fulvene-type compound that isreadily separated from the desired fulvene. In this aspect, for example,this disclosure provides a method of isolating a fulvene from acomposition comprising the fulvene and at least onecyclopentadiene-containing impurity, comprising:

-   -   a) contacting the composition with        4-(N,N-dimethylamino)benzaldehyde, pyrrolidine, and optionally a        first solvent to provide a first mixture;    -   b) contacting the first mixture with an aqueous acid to provide        a second mixture;    -   c) extracting the second mixture with a second solvent to        provide an extract, optionally concentrating the extract, and        optionally drying the extract; and    -   d) isolating the fulvene from the extract by chromatography;        wherein:

the fulvene has the formula C₄R³ ₄C═CR¹R² and the structural formula

R¹, R², and R³, in each occurrence, are independently a hydrocarbylgroup having up to 20 carbon atoms, or hydrogen.

This purification procedure can be employed in any of several fulvenesynthetic methods. For example, in this aspect, this disclosure providesa method of making a fulvene having the formula C₄R⁶ ₄C═CR⁴CH₂R⁵, andthe structural formula

comprising:

-   -   a) contacting in an aprotic first solvent a ketone of the        formula O═CR⁴CH₂R⁵ and a cyclopentadienyl compound selected from        Mg(C₅R⁶ ₄H)X, Mg(C₅R⁶ ₄H)₂, or a combination thereof, to provide        a first mixture;    -   b) contacting the first mixture with a proton source, to form a        fulvene composition comprising the fulvene and optionally at        least one cyclopentadiene-containing impurity;    -   c) contacting the fulvene composition with        4-(N,N-dimethylamino)-benzaldehyde, pyrrolidine, and optionally        a second solvent to provide a second mixture;    -   d) contacting the second mixture with an aqueous acid to provide        a third mixture;    -   e) extracting the third mixture with a third solvent to provide        an extract, optionally concentrating the extract, and optionally        drying the extract; and    -   f) isolating the fulvene from the extract by chromatography;        wherein:    -   R⁴ is an aryl or substituted aryl group having up to 20 carbon        atoms;    -   R⁵ is a hydrocarbyl or substituted hydrocarbyl group having up        to 20 carbon atoms, or hydrogen;    -   R⁶, in each instance, is independently selected from a        hydrocarbyl or substituted hydrocarbyl group having up to 20        carbon atoms, or hydrogen; and    -   X is Cl, Br, or I.

The purification procedure disclosed herein can also be employed in anyof several bis(cyclopentadienyl)-type ligand syntheses, includingbis(cyclopentadienyl), cyclopentadienyl-indenyl, andcyclopentadienyl-fluorenyl type ligands. For example, in another aspect,this disclosure provides a method of making a compound having theformula C₄R⁶ ₄CHCR⁴(CH₂R⁵)(QH) and the structural formula

comprising:

-   -   a) contacting in an aprotic first solvent a ketone of the        formula O═CR⁴CH₂R⁵ and a cyclopentadienyl compound selected from        Mg(C₅R⁶ ₄H)X, Mg(C₅R⁶ ₄H)₂, or a combination thereof, to provide        a first mixture;    -   b) contacting the first mixture with a proton source, to form a        fulvene composition comprising the fulvene and optionally at        least one cyclopentadiene-containing impurity;    -   c) contacting the fulvene composition with        4-(N,N-dimethylamino)-benzaldehyde, pyrrolidine, and optionally        a second solvent to provide a second mixture;    -   d) contacting the second mixture with an aqueous acid to provide        a third mixture;    -   e) extracting the third mixture with a third solvent to provide        an extract, optionally concentrating the extract, and optionally        drying the extract; and    -   f) isolating the fulvene from the extract by chromatography;    -   g) contacting the fulvene with MQ, followed by a proton source,        to form C₄R⁶ ₄CHCR⁴(CH₂R⁵)(QH), wherein M is Li, Na, K, MgX,        Mg_(0.5), and wherein Q is a cyclopentadienyl, an indenyl, a        fluorenyl, or a substituted analog thereof, wherein    -   R⁴ is an aryl or substituted aryl group having up to 20 carbon        atoms;    -   R⁵ is a hydrocarbyl or substituted hydrocarbyl group having up        to 20 carbon atoms, or hydrogen;    -   R⁶, in each instance, is independently selected from a        hydrocarbyl or substituted hydrocarbyl group having up to 20        carbon atoms, or hydrogen; and    -   X is Cl, Br, or I.

These and other features, aspects, embodiments, and advantages of thepresent invention will become apparent after a review of the followingdetailed description of the disclosed features.

The following publication and patent are incorporated herein byreference in their entireties: U.S. Patent Application Publication No.2005/0288524; and U.S. Pat. No. 7,064,225.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates the ¹H NMR spectrum of the crude reaction productisolated from the reaction of CpMgCl and pentatriacontanone intetrahydrofuran (THF).

FIG. 2 illustrates the ¹H NMR spectrum of the product isolated from thereaction of CpMgCl and pentatriacontanone in tetrahydrofuran (THF),following chromatography over silica (n-pentane eluent) prior toobtaining the spectrum.

FIG. 3 illustrates the ¹H NMR spectrum of the product arising from thereaction of CpMgCl and pentatriacontanone in tetrahydrofuran (THF), inwhich the crude reaction product was reacted with4-(N,N-dimethylamino)benzaldehyde/pyrrolidine according to thisdisclosure, following chromatography over silica (n-pentane eluent)prior to obtaining the spectrum.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides, among other things, a method ofpurifying fulvenes, including a method of removing undesirableregioisomers from the desired fulvene in a crude fulvene composition. Inone aspect, the disclosed method includes selectively reacting theseundesirable regioisomers with pyrrolidine and4-(N,N-dimethylamino)benzaldehyde, according to the method disclosed inJ. Org. Chem. 1984, 49, 1849-1853, and in Organometallics 1999, 18,4098-4106, both of which are incorporated herein by reference in theirentireties. In this aspect, for example, this disclosure provides amethod of isolating a fulvene from a composition comprising the fulveneand at least one cyclopentadiene-containing impurity, comprising:

-   -   a) contacting the composition with        4-(N,N-dimethylamino)benzaldehyde, pyrrolidine, and optionally a        first solvent to provide a first mixture;    -   b) contacting the first mixture with an aqueous acid to provide        a second mixture;    -   c) extracting the second mixture with a second solvent to        provide an extract, optionally concentrating the extract, and        optionally drying the extract; and    -   d) isolating the fulvene from the extract by chromatography;        wherein:

the fulvene has the formula

R¹, R², and R³, in each occurrence, are independently a hydrocarbylgroup having up to 20 carbon atoms, or hydrogen.

While not intending to be bound by theory, Scheme 2 illustrates some ofthe cyclopentadiene-containing impurities that may be present in afulvene composition. Specifically, Scheme 2 illustrates undesiredisomers 4 and 5 that can form along with the desired fulvene 2 in atypical fulvene synthesis step, arising from different regiochemistriesof dehydration of the intermediate alcohol 3. The presence ofsubstituted cyclopentadienes 4 and 5 can be problematic during theligand preparation illustrated in Scheme 1, because the reaction of thefulvene composition with nucleophilic cyclopentadienyl (Cp), indenyl(Ind), or fluorenyl (Flu) reagents can result in the nucleophile simplydeprotonating 4 and 5 and become unavailable for the desired reactionwith fulvene.

Again, while not intending to be bound by theory, in one aspect, thisdisclosure provides a method of separating the desired fulvene 2 fromthe undesired cyclopentadiene-containing impurities such as 4 and 5 byselectively reacting the undesired isomers to form a product that iseasily separated from fulvene 2. Thus, in one aspect, this inventionprovides methods of reacting these undesired regioisomers withpyrrolidine and 4-(N,N-dimethylamino)benzaldehyde to form anothersubstituted fulvene 6, illustrated in Scheme 3, which is readilyseparated from the desired fulvene by chromatographic or other standardseparation methods.

The Examples and the Figures provided herein illustrate various aspectsof this invention. The preparation of 6,6-diheptadecylpentafulvene fromthe reaction of pentatriacontanone, ([CH₃(CH₂)₁₆]₂CO) and CpMgCl in THFis provided in Example 1. The ¹H NMR spectrum of FIG. 1 illustrates thatthe crude product is a mixture of the desired6,6-diheptadecylpentafulvene and isomeric alkenylcyclopentadienes, wherethe presence of the undesired substituted cyclopentadiene isomers isseen by the ¹H NMR resonances near 3 ppm, arising from the two hydrogenatoms bonded to the same carbon atom of the cyclopentadiene ring. Thetwo resonances indicate the presence of two isomers in differentamounts.

Example 2 and FIG. 2 disclose the results of attempting to purify the6,6-diheptadecylpentafulvene from Example 1 using standardchromatographic methods. FIG. 2 illustrates the ¹H NMR spectrum of theproduct arising from the reaction of CpMgCl and pentatriacontanone intetrahydrofuran (THF), following chromatography over silica (n-pentaneeluent) prior to obtaining the spectrum, which is seen to remove theresidual THF only and is not effective in removing the isomericalkenylcyclopentadienes.

Example 3 and FIG. 3 illustrate the purification of6,6-diheptadecylpentafulvene according to the present invention. FIG. 3illustrates the ¹H NMR spectrum of the pure 6,6-diheptadecylpentafulveneproduct arising from the reaction of CpMgCl and pentatriacontanone inTHF, in which the crude reaction product was reacted with4-(N,N-dimethylamino)benzaldehyde/pyrrolidine, following chromatographyover silica (n-pentane eluent) prior to obtaining the spectrum. Thus,the crude reaction product was reacted with4-(N,N-dimethylamino)benzaldehyde in a mixture of methylene chloride andmethanol, using pyrrolidine according to the method of Stone and Little(J. Org. Chem. 1984, 49, 1849-1853), which resulted in a dark redviscous liquid. The red mixture was easily separated by chromatographyover silica using n-pentane to elute the pure, yellow fulvene compound,while the dark red derivative of the side products remained on thecolumn

In still another aspect, this invention provides a method of isolating afulvene from a composition comprising the fulvene and at least onecyclopentadiene-containing impurity, as disclosed above, wherein thefulvene has the formula C₄R³ ₄C═CR¹R² and the structural formula

and wherein R¹ and R² can be selected independently from: a) a linear ora branched alkyl group; b) a linear or a branched alkenyl group; c) anaryl group; or d) an aryl-substituted linear or branched alkyl group;any of which having up to 20 carbon atoms. Moreover, another aspect ofthis invention provides that R¹ and R² are, independently, an alkylgroup having from 1 to 18 carbon atoms. In another aspect, R³, in eachoccurrence, can be selected independently from: a) a linear or abranched alkyl group having up to 12 carbon atoms; or b) hydrogen.

Yet another aspect of this invention provides that the fulvene can havethe formula:

R³, in each occurrence, is independently a linear or a branched alkylgroup having up to 6 carbon atoms; m is 0, 1, 2, 3, or 4; and n is aninteger from 1 to 16. In a related aspect, the fulvene can have theformula illustrated immediately above, wherein R³, in each occurrence,is independently a linear or a branched alkyl group having up to 6carbon atoms; m is 0, 1, 2, 3, or 4; and n is an integer from 6 to 16.Further, the desired fulvene according to the present invention can alsohave the formula C₄H₄C═C[(CH₂)₁₆CH₃]₂.

An additional aspect of this invention provides that the at least onecyclopentadiene-containing impurity can be

or a combination thereof, wherein n is an integer from 1 to 16. In arelated aspect, this disclosure provides that the at least onecyclopentadiene-containing impurity can be

a combination thereof, wherein n is an integer from 6 to 16. Anadditional aspect of this invention provides that the at least onecyclopentadiene-containing impurity can be

or a combination thereof.

In yet another aspect of the invention, the method of isolating afulvene from a composition comprising the fulvene and at least onecyclopentadiene-containing impurity, comprising:

-   -   a) contacting the composition with        4-(N,N-dimethylamino)benzaldehyde, pyrrolidine, and optionally a        first solvent to provide a first mixture;    -   b) contacting the first mixture with an aqueous acid to provide        a second mixture;    -   c) extracting the second mixture with a second solvent to        provide an extract, optionally concentrating the extract, and        optionally drying the extract; and    -   d) isolating the fulvene from the extract by chromatography;        wherein the fulvene has the formula C₄R³ ₄C═CR¹R² wherein R¹,        R², and R³ can be as disclosed herein, and wherein the first        solvent can be a mixture of methylene chloride and an alcohol        having up to 4 carbon atoms. Further to this aspect, the first        solvent can be a mixture of methylene chloride and methanol.        Moreover, another aspect of this invention provides that the        second solvent can be an alkane having up to about 12 carbon        atoms, including, but not limited to, pentane, hexane, heptane,        or any combination thereof.

In yet another aspect of this invention, this disclosure provides thatthe aqueous acid employed in contacting the first mixture to provide asecond mixture can be any aqueous acid, including organic acids orinorganic acids. The acid can also be a weak aqueous acid or a strongaqueous acid. Thus, useful acids can be selected from, but are notlimited to, acetic acid, trifluoroacetic acid, formic acid, hydrochloricacid, phosphoric acid, sulfuric acid, nitric acid, or any combinationthereof. The aqueous acid can also be ammonium salts including aqueoussolutions of ammonium salts, and the like.

Still other aspects of this invention can be seen in the isolation ofthe fulvene from the extract, according to the present disclosure. Thus,the isolation of the purified fulvene from the extract can beaccomplished by any method as would be recognized by one of ordinaryskill, which is typically, but not limited to, chromatography. Forexample, depending on the particular substituents on the fulvene, asolid fulvene compound could be formed and purified by crystallizationfrom solution according methods understood by one of ordinary skill inthe art. When the fulvene is isolated from the extract bychromatography, the extract can be concentrated, dried, or both prior tochromatography if desired.

The purification procedure disclosed herein can be employed in any ofseveral fulvene synthetic methods, including, but not limited to thereaction of a ketone O═CRR′ with an anionic cyclopentadienyl reagentsuch as Li[C₅R″₄H] or Na[C₅R″₄H], typically in alcoholic solvents, or inethereal solvents followed by reaction of the resulting mixture with aproton source. For example, in this aspect, this disclosure provides amethod of making a fulvene having the formula C₄R⁶ ₄C═CR⁴CH₂R⁵, and thestructural formula

comprising:

-   -   a) contacting in an aprotic first solvent a ketone of the        formula O═CR⁴CH₂R⁵ and a cyclopentadienyl compound selected from        Mg(C₅R⁶ ₄H)X, Mg(C₅R⁶ ₄H)₂, or a combination thereof, to provide        a first mixture;    -   b) contacting the first mixture with a proton source, to form a        fulvene composition comprising the fulvene and optionally at        least one cyclopentadiene-containing impurity;    -   c) contacting the fulvene composition with        4-(N,N-dimethylamino)-benzaldehyde, pyrrolidine, and optionally        a second solvent to provide a second mixture;    -   d) contacting the second mixture with an aqueous acid to provide        a third mixture;    -   e) extracting the third mixture with a third solvent to provide        an extract, optionally concentrating the extract, and optionally        drying the extract; and    -   f) isolating the fulvene from the extract by chromatography;        wherein:    -   R⁴ and R⁵ are, independently, a hydrocarbyl or substituted        hydrocarbyl group having up to 20 carbon atoms, or hydrogen;    -   R⁶, in each occurrence, is independently selected from a        hydrocarbyl or substituted hydrocarbyl group having up to 20        carbon atoms, or hydrogen; and    -   X is Cl, Br, or I.

Thus, in one aspect of the method of preparing a fulvene having theformula C₄R⁶ ₄C═CR⁴CH₂R⁵ disclosed herein, R⁴ and R⁵ can be,independently, an alkyl, aryl, alkenyl, or a substituted analog thereof,having up to 20 carbon atoms, or hydrogen. Further, R⁵ can be an alkylor alkenyl having from 3 to 10 carbon atoms. In further aspects of thepreparation of a fulvene C₄R⁶ ₄C═CR⁴CH₂R⁵ disclosed herein, CH₂R⁵ canbe:

(CH₂)_(x)CH₃, wherein x is an integer from 1 to 10;

(CH₂)_(y)CH═CH₃, wherein y is an integer from 1 to 10;

CH₂CH₂C(CH₃)═CH₂;

CH₂CH₂CH═C(CH₃)₂;

CH₂C₆H₅;

CH₂C₆H_(z-5)Me_(z), wherein z is an integer from 0 to 3;

CH₂C₆H₄(C₆H₁₁);

CH₂C₆H₄(C₆H₅);

CH₂C₆H₄(C₄H₉); or

a substituted analog thereof having up to 20 carbon atoms.

In other aspects of the preparation of a fulvene C₄R⁶ ₄C═CR⁴CH₂R⁵disclosed herein, the cyclopentadienyl compound can be, but is notlimited to, Mg(C₅H₅)Cl, Mg(C₅H₅)Br, or a combination thereof. Moreover,for the typical cyclopentadienyl compound is Mg(C₅H₅)X wherein X is Clor Br, the molar ratio of Mg(C₅H₅)X to ketone can be greater than 1. Ina further aspect, the molar ratio of Mg(C₅H₅)X to ketone can be greaterthan 1.2, or the molar ratio of Mg(C₅H₅)X to ketone can be greater than1.5.

In yet further aspects of the preparation of a fulvene C₄R⁶ ₄C═CR⁴CH₂R⁵disclosed herein, the first aprotic solvent is dimethyl ether, diethylether, diisopropyl ether, di-n-propyl ether, di-n-butyl ether, methylt-butyl ether, diphenyl ether, THF, 1,2-dimethoxyethane, or anycombination thereof. The second solvent can be a mixture of methylenechloride and an alcohol having up to 4 carbon atoms, for example, thesecond solvent can be a mixture of methylene chloride and methanol.Moreover, another aspect of this invention provides that the thirdsolvent can be an alkane having up to about 12 carbon atoms, including,but not limited to, pentane, hexane, heptane, or any combinationthereof.

Thus, in another aspect of the method of preparing a fulvene C₄R⁶₄C═CR⁴CH₂R⁵ disclosed herein, the proton source can be any compound orcombination of compounds that can serve as a source of protons to theformal anion formed upon reacting the ketone with the cyclopentadienylreagent. In this aspect, for example, the proton source can be water, anacid including an aqueous acid, ammonium salts including aqueoussolutions of ammonium salts, and the like. For example, aqueous HCl canbe used as the proton source in this reaction.

In yet another aspect of the method of preparing a fulvene C₄R⁶₄C═CR⁴CH₂R⁵, this disclosure provides that the aqueous acid employed incontacting the second mixture to provide a third mixture can be anyaqueous acid, including organic acids or inorganic acids. The acid canalso be a weak aqueous acid or a strong aqueous acid. Thus, useful acidscan be selected from, but are not limited to, acetic acid,trifluoroacetic acid, formic acid, hydrochloric acid, phosphoric acid,sulfuric acid, nitric acid, or any combination thereof. The aqueous acidcan also be ammonium salts including aqueous solutions of ammoniumsalts, and the like.

Still other aspects of this invention can be seen in the isolation ofthe fulvene from the extract, according to the present disclosure. Thus,the isolation of the purified fulvene from the extract can beaccomplished by any method as would be recognized by one of ordinaryskill, which is typically, but not limited to, chromatography, in themanner disclosed above for purifying the fulvene. Thus, for example,when the fulvene is isolated from the extract by chromatography, theextract can be concentrated, dried, or both prior to chromatography ifdesired. Depending on the particular substituents on the fulvene, asolid fulvene compound could be purified according to this disclosure,that could be crystallized from solution according methods understood byone of ordinary skill in the art.

As recognized by one of ordinary skill, when the fulvene is isolated bychromatography, any suitable chromatographic support can be employed, asthis step is not limited to a specific type of solid support. Rather alarge number of supports are available and are known to one skilled inthe art. Solid supports include, but are not limited to, silica gels,resins, derivatized plastic films, glass beads, cotton, plastic beads,polystyrene beads, alumina gels, polysaccharides, and the like. Forexample, suitable chromatographic supports include silica, alumina,silica-alumina, aluminum phosphate, titania, silica-titania, zirconia,zinc oxide, mixed oxides thereof, or any mixture thereof.

The present invention also encompasses a method of synthesizingcompounds comprising cyclopentadienyl-type moieties that are linked by a>CR¹(CH₂R²) group, namely bis(cyclopentadienyl)methane compounds, andvarious analogs thereof such as (cyclopentadienyl)(indenyl)methane and(cyclopentadienyl)(fluorenyl)methane compounds. Thus, in still a furtheraspect of the present invention provides a method of making a compoundhaving the formula C₄R⁶ ₄CHCR⁴(CH₂R⁵)(QH) and the structure

comprising:

-   -   a) contacting in an aprotic first solvent a ketone of the        formula O═CR⁴CH₂R⁵ and a cyclopentadienyl compound selected from        Mg(C₅R⁶ ₄H)X, Mg(C₅R⁶ ₄H)₂, or a combination thereof, to provide        a first mixture;    -   b) contacting the first mixture with a proton source, to form a        fulvene composition comprising the fulvene and optionally at        least one cyclopentadiene-containing impurity;    -   c) contacting the fulvene composition with        4-(N,N-dimethylamino)-benzaldehyde, pyrrolidine, and optionally        a second solvent to provide a second mixture;    -   d) contacting the second mixture with an aqueous acid to provide        a third mixture;    -   e) extracting the third mixture with a third solvent to provide        an extract, optionally concentrating the extract, and optionally        drying the extract; and    -   f) isolating the fulvene from the extract by chromatography;    -   g) contacting the fulvene with MQ followed by a proton source,        to form C₄R⁶ ₄CHCR⁴(CH₂R⁵)(QH), wherein M is Li, Na, K, MgX, or        Mg_(0.5), and wherein Q is a cyclopentadienyl, an indenyl, a        fluorenyl, or a substituted analog thereof, wherein    -   R⁴ and R⁵ are, independently, a hydrocarbyl or substituted        hydrocarbyl group having up to 20 carbon atoms, or hydrogen;    -   R⁶, in each occurrence, is independently selected from a        hydrocarbyl or substituted hydrocarbyl group having up to 20        carbon atoms, or hydrogen; and    -   X is Cl, Br, or I.

In this aspect, when Q is selected from a substituted cyclopentadienyl,a substituted indenyl, or a substituted fluorenyl, any substituent on Qcan be selected independently from R^(4A), wherein R^(4A) can be analiphatic or substituted aliphatic group having from 1 to about 20carbon atoms, or hydrogen. Any possible substituents on R⁴, R⁵, R⁶, orR^(4A) are disclosed herein.

Also in this aspect of this invention, the preparation and isolation ofthe fulvene is disclosed above. The additional steps in synthesizingC₄R⁶ ₄CHCR⁴(CH₂R⁵)(QH) include, for example, contacting the fulvene withMQ followed by a proton source, to form C₄R⁶ ₄CHCR⁴(CH₂R⁵)(QH), whereinM is Li, Na, K, MgX (X is Cl, Br, or I), or Mg_(0.5), and wherein Q is acyclopentadienyl, an indenyl, a fluorenyl, or a substituted analogthereof. The methods and details of these preparative steps aredisclosed in U.S. Patent Application Publication No. 2005/0288524, andentirety of which is incorporated herein by reference.

Numerous processes to prepare and use metallocene-based catalyst thatcan be employed with ligands such as C₄R⁶ ₄CHCR⁴(CH₂R⁵)(QH) that isdisclosed in this invention have been reported. For example, U.S. Pat.Nos. 4,939,217, 5,191,132, 5,210,352, 5,347,026, 5,399,636, 5,401,817,5,420,320, 5,436,305, 5,451,649, 5,496,781, 5,498,581, 5,541,272,5,554,795, 5,563,284, 5,565,592, 5,571,880, 5,594,078, 5,631,203,5,631,335, 5,654,454, 5,668,230, 5,705,478, 5,705,579, 6,187,880,6,509,427, and 6,524,987 all describe such methods. Other processes toprepare metallocene compounds that can be employed in this inventionhave been reported in references such as: Köppl, A. Alt, H. G. J. Mol.Catal A. 2001, 165, 23; Kajigaeshi, S.; Kadowaki, T.; Nishida, A.;Fujisaki, S. The Chemical Society of Japan, 1986, 59, 97; Alt, H. G.;Jung, M.; Kehr, G. J. Organomet. Chem. 1998, 562, 153-181; and Alt, H.G.; Jung, M. J. Organomet. Chem. 1998, 568, 87-112, each of which isincorporated by reference herein, in their entireties. Further,additional processes to prepare metallocene compounds that can beemployed in this invention have been reported in: Journal ofOrganometallic Chemistry, 1996, 522, 39-54, which is incorporated byreference herein, in its entirety. The following treatises also describesuch methods: Wailes, P. C.; Coutts, R. S. P.; Weigold, H. inOrganometallic Chemistry of Titanium, Zirconium, and Hafnium, Academic;New York, 1974.; Cardin, D. J.; Lappert, M. F.; and Raston, C. L.;Chemistry of Organo-Zirconium and -Hafnium Compounds; Halstead Press;New York, 1986.

In a further aspect of the present invention, this disclosureencompasses additional methods for the synthesis of organic compoundscomprising two cyclopentadienyl-type groups linked by a bridging group,which are useful ligands in preparing ansa-metallocene complexes that,in turn, can be used subsequently as catalyst components in olefinpolymerizations. These methods can generally afford higher yields of thedesired product than were heretofore available and can permit a range ofsubstituents to be incorporated into the ligand and theansa-metallocene. These additional methods for preparing organiccompounds comprising two cyclopentadienyl-type groups linked by abridging group have been disclosed in U.S. Pat. No. 7,064,225, which isincorporated by reference herein in its entirety.

In this aspect of this invention, a method is provided for the synthesisof compounds comprising linked cyclopentadienyl and fluorenyl groups,including substituted analogs thereof, which are precursors toansa-metallocenes comprising bridged cyclopentadienyl and fluorenylligands. However, this method is also applicable to ligands comprisinglinked cyclopentadienyl and indenyl groups, indenyl and fluorenylgroups, two cyclopentadienyl groups, two indenyl groups, or twofluorenyl groups. This invention is specifically illustrated by thedisclosure and examples of U.S. Pat. No. 7,064,225 for preparing linkedcyclopentadienyl and fluorenyl groups and ansa-metallocenes comprisingbridged cyclopentadienyl and fluorenyl ligands. This method utilized afulvene compound, which can be a fulvene that is purified according tothe purification methods and/or prepared according to the preparativemethods of this disclosure. In this aspect, for example, this inventionprovides a new high-yield method for making the metallocene,(5-cyclopentadienyl)[5-(2,7-di-tert-butylfluorenyl)]hex-1-ene zirconiumdichloride, as well as its parent ligand,(5-cyclopentadienyl)[5-(2,7-di-tert-butylfluorenyl)]hex-1-ene. However,many variations in the substitution patterns for this ligand andansa-metallocene are possible, as disclosed herein.

In one aspect, this invention also provides a method for making acompound of the formula

and isomers thereof, comprising:

a) contacting a compound of the formula

and an alkyl lithium reagent in an ethereal solvent to form a firstmixture, wherein compound II is substantially deprotonated to formLi⁺[II⁻];

b) rapidly combining the first mixture with a fulvene compound of theformula

to form a second mixture, wherein either Li⁺[II⁻] or compound III isoptionally a limiting reagent, and wherein the limiting reagent, ifpresent, has substantially reacted; and

c) contacting the second mixture with a proton source to form a thirdmixture comprising

and isomers thereof;

wherein R^(1A) and R^(2A) independently are hydrogen or an aliphatic orsubstituted aliphatic group having from 1 to about 20 carbon atoms; and

wherein each R^(3A) independently is hydrogen or an aliphatic orsubstituted aliphatic group having from 1 to about 20 carbon atoms.

Possible substituents for R^(1A), R^(2A), and R^(3A) are providedherein. Typically, compound I is formed in at least about 85% yield, atleast about 90% yield, or at least about 95% yield. Thus, in thismethod, the fulvene compound of the formula III used to form a secondmixture can be a fulvene that is purified and/or prepared according tothis disclosure.

For example, compounds of the formula I that can be prepared using thisinvention include the compound of the formula

which can be prepared as disclosed herein using the precursors

and compound III having the specific formula

wherein R^(3A) can be typically H, t-butyl, i-propyl, n-propyl, ethyl,or methyl, and wherein n is an integer from 1 to about 6.

Further to this aspect of the invention, the concentration of theLi⁺[II⁻] reagent in the first mixture prior to rapidly combining thefirst mixture with III, can be from about 0.5 M to about 1.8 M.Alternatively, the concentration of the Li⁺[II⁻] reagent in the firstmixture prior to rapidly combining the first mixture with III, can befrom about 0.7 M to about 1.5 M.

The alkyl lithium reagent of this aspect of the invention can compriseMeLi, n-BuLi, t-BuLi, n-hexylLi, LiCH₂SiMe₃, LiCH₂Ph, LiCH₂CMe₃, or anycombination thereof. In this aspect, compound II and the alkyl lithiumreagent can react to form Li⁺[II⁻] in at least about 95% yield.Generally, the first mixture can be combined with III over a time periodof less than about 5 minutes, less than about 3 minutes, less than about1 minute, less than about 30 seconds, or less than about 15 seconds.

In a further aspect, the proton source can comprise water, an aqueousacid, an aqueous ammonium salt, or any combination thereof. Further,step a can be initiated from about 0° C. to about −100° C. For example,step a can be initiated at about −78° C. In yet another aspect, step acan be conducted from about room temperature to about −78° C. Step b, inanother aspect, can be initiated from about 0° C. to about −100° C. Forexample, step b can be initiated at about −78° C. In still anotheraspect, step b can be conducted from about room temperature to about−78° C.

Still another aspect of this disclosure provides that the limitingreagent of step b in the above process can be present in at least about50% the mole fraction of the non-limiting reagent. In a further aspectof this invention, at least about 90% of the limiting reagent of step bcan react, or at least about 95% of the limiting reagent of step b canreact. Yet another aspect of this disclosure is that compound I isformed in at least about 85% yield, at least about 90% yield, or atleast about 95% yield.

In another aspect, this invention provides a method of making a compoundof the formula

and isomers thereof, comprising:

a) providing a source of a fluorenyl anion having the formula

b) rapidly combining the source of the fluorenyl anion with a fulvenecompound of the formula

to form a mixture, wherein either the source of the fluorenyl anion orcompound III is optionally a limiting reagent, and wherein the limitingreagent, if present, has substantially reacted; and

c) contacting the mixture with a proton source to form

and isomers thereof,

wherein R^(1A) and R^(2A) independently are hydrogen or an aliphatic orsubstituted aliphatic group having from 1 to about 20 carbon atoms; and

wherein each R^(3A) independently is hydrogen or an aliphatic orsubstituted aliphatic group having from 1 to about 20 carbon atoms. Inthis aspect, for example, the source of the fluorenyl anion having theformula

can typically comprise lithium, sodium, potassium, magnesium, calcium,or a combination thereof, in addition to comprising the fluorenyl anion.For example, the source of the fluorenyl anion having the formula

can typically comprise a salt of the fluorenyl anion comprising lithium,sodium, potassium, magnesium, calcium, or a combination thereof.

The ethereal solvent used in this method, can be independently selectedfrom a range of ethereal solvents, including, but not limited to,dimethyl ether, diethyl ether, diisopropyl ether, di-n-propyl ether,di-n-butyl ether, methyl t-butyl ether, diphenyl ether, THF,1,2-dimethoxyethane, or any combination thereof.

In another aspect of the invention, the rapid combination of theethereal solution of the fluorenyl component Li⁺[II⁻] and the fulvenecompound III, is typically carried out over a time period of less thanabout 1 minute. This combination time for the fluorenyl and the fulvenecompounds is different than the total contact time between thesecompounds, prior to proceeding to the subsequent step in the process.The combination time describes the elapsed time over which the additionof the fulvene to the ethereal solution of the fluorenyl, oralternatively, the addition of the ethereal solution of fluorenecompound to the fulvene, is initiated and completed.

This method can further comprise isolating compound I. For example, themethod of this invention can further comprise removing the volatilecomponents from the third mixture to provide a residue comprising I,optionally triturating the residue with a solvent in which I issubstantially insoluble and III is soluble, and isolating I. Examples ofsolvents that are useful in this trituration include, but are notlimited to, alcohols having up to about 8 carbon atoms, examples ofwhich include, but are not limited to methanol, ethanol, i-propanol,n-propanol, n-butanol, sec-butanol, t-butanol, 1-hexanol, 2-hexanol,3-hexanol, any mixture thereof, or any combination thereof.

In a further aspect of this invention, a method is provided for makingan ansa-metallocene compound of the formula

comprising:

a) contacting a compound of the formula

and a first alkyl lithium reagent in a first ethereal solvent to form afirst mixture, wherein compound II is substantially deprotonated to formLi⁺[II⁻];

b) rapidly combining the first mixture with a fulvene compound of theformula

to form a second mixture, wherein the limiting reagent has substantiallyreacted;

c) contacting the second mixture with a proton source to form a thirdmixture comprising

including isomers thereof, in at least about 85% yield;

d) removing the volatile components from the third mixture to provide aresidue comprising I;

e) optionally triturating the residue with a solvent in which I issubstantially insoluble and III is soluble to provide I, followed byisolation of I;

f) contacting the I with from about 2 to about 2.5 molar equivalents ofa second alkyl lithium reagent in a second ethereal solvent to form afourth mixture, wherein the I is substantially deprotonated to form Li⁺₂[I²⁻];

g) contacting the fourth mixture with M¹X₄ and an optional hydrocarboncosolvent to form a fifth mixture comprising

h) removing the volatile components from the fifth mixture to provide IVin at least about 80% yield;

i) optionally washing the IV in a non-polar solvent;

j) optionally extracting the IV with a polar solvent followed byremoving the volatiles from the polar solvent solution to provide IV;and

k) optionally crystallizing the IV from an aromatic solvent;

wherein:

R^(1A) and R^(2A) are independently selected from an aliphatic orsubstituted aliphatic group having from 1 to about 20 carbon atoms, orhydrogen; and

R^(3A), in each instance, is independently selected from an aliphatic orsubstituted aliphatic group having from 1 to about 20 carbon atoms, orhydrogen;

M¹ is Zr or Hf; and

X is Cl, Br, or I.

It was found that yields of the metallocene were improved when thevolatile components were removed from the fifth mixture to provide IV.

This method can also be used to prepare a zirconocene analog having thestructure

according to the method disclosed herein, wherein compound I has theformula

compound If has the formula

and compound III has the formula

wherein:

R³ is H, t-butyl, i-propyl, n-propyl, ethyl, or methyl; and

n is an integer from 1 to about 6.

In one aspect, the first and second alkyl lithium reagents can beselected independently from, for example, MeLi, n-BuLi, t-BuLi,n-hexylLi, LiCH₂SiMe₃, LiCH₂Ph, LiCH₂CMe₃, or any combination thereof.In a further aspect, the first mixture can be combined with III over atime period of less than about 3 minutes, over a time period of lessthan about 1 minute, or over a time period of less than about 30seconds. Moreover, the compound II and the first alkyl lithium reagentcan react to form Li⁺[II⁻] in at least about 95% yield, and the fourthmixture can comprise Li⁺ ₂[I²⁻] in at least about 90% yield.

In a further aspect of the invention, the rapid combination of afluorenyl component Li⁺[II⁻] with a fulvene component III is typicallycarried out over a time period of less than about 5 minutes, less thanabout 3 minutes, less than about 1 minute, or less than about 15seconds. This combination time for the fluorenyl and the fulvenecompounds is different than the total contact time between thesecompounds, prior to proceeding to the subsequent step in the process.

The first and second ethereal solvents used in the preparation of themetallocene can be independently selected from a range of etherealsolvents, including, but not limited to, dimethyl ether, diethyl ether,diisopropyl ether, di-n-propyl ether, di-n-butyl ether, methyl t-butylether, diphenyl ether, THF, 1,2-dimethoxyethane, or any combinationthereof.

This method of preparing the metallocene, which comprises removing thevolatile components from the third mixture to provide a residuecomprising I, can also optionally comprise triturating the residue witha solvent in which I is substantially insoluble and III is soluble toprovide I, followed by isolation of I. Examples of solvents that areuseful in this trituration include, but are not limited to, alcoholshaving up to about 8 carbon atoms, examples of which include, but arenot limited to methanol, ethanol, i-propanol, n-propanol, n-butanol,sec-butanol, t-butanol, 1-hexanol, 2-hexanol, 3-hexanol, any mixturethereof, or any combination thereof. In one aspect, the optionalhydrocarbon cosolvent and the non-polar solvent can be selectedindependently from butane, pentane, cyclopentane, hexane, heptane,cyclohexane, methyl cyclopentane, octane, or any combination thereof.The polar solvent disclosed in the method can be selected from, forexample, CHCl₃, CH₂Cl₂, 1,2-dichlorethane, or any combination thereof.Further, the aromatic solvent can be selected from benzene, toluene,xylene, mesitylene, ethyl benzene, anisole, aniline, or any combinationthereof.

In yet another aspect of this invention, this disclosure provides amethod of isolating a compound of the formula C₄R³ ₄C═CR¹R² and methodsof making compounds of the formulas: C₄R⁶ ₄C═CR⁴CH₂R⁵; C₄R⁶₄CHCR⁴(CH₂R⁵)(QH), wherein Q is a cyclopentadienyl, an indenyl, or afluorenyl; and

as described above. As disclosed herein, R⁴, R⁵ and R⁶, independently,can be a substituted hydrocarbyl groups, and R^(1A), R^(2A), R^(3A), andR^(4A), independently, can be a substituted aliphatic group. Moreover, Qcan be a substituted cyclopentadienyl, a substituted indenyl, or asubstituted fluorenyl, in which any substituent on Q can be selectedindependently from R^(4A).

In this aspect, any substituent on R⁴, R⁵, R⁶, R^(1A), R^(2A), R^(3A),or R^(4A), can be selected independently from an aliphatic group, anaromatic group, a cyclic group, a combination of aliphatic and cyclicgroups, an oxygen group, a sulfur group, a nitrogen group, a phosphorusgroup, an arsenic group, a carbon group, a silicon group, a germaniumgroup, a tin group, a boron group, an aluminum group, or hydrogen, andthe like. These substituents can be further described herein as follows.In each of the examples presented herein, unless otherwise specified, Ris independently selected from H, an aliphatic group, an aromatic group,or a cyclic group, having from 1 to about 20 carbon atoms.

Examples of aliphatic groups, in each instance, include but are notlimited to, hydrocarbyls such as paraffins and olefins having from 1 toabout 20 carbon atoms. Thus, aliphatic groups, in each instance,include, but are not limited to, an alkyl group, a cycloalkyl group, analkenyl group, a cycloalkenyl group, an alkynyl group, an alkadienylgroup, a cyclic group, and the like, and includes all branched andlinear analogs thereof, in each instance having from 1 to about 20carbon atoms. For example, aliphatic groups as used herein includemethyl, ethyl, propyl, n-butyl, tert-butyl, sec-butyl, isobutyl, amyl,isoamyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, dodecyl,2-ethylhexyl, pentenyl, butenyl, and the like. Aliphatic groups includealkenyl groups, alkynyl groups, alkadienyl groups, and the like, havingfrom 1 to about 20 carbon atoms, including any regioisomer thereof.

Examples of aromatic groups include, but are not limited to, phenyl,naphthyl, anthracenyl, and the like.

Examples of cyclic groups include, but are not limited to,cycloparaffins, cycloolefins, cycloacetylenes, arenes such as phenyl,bicyclic groups and the like, including substituted derivatives thereof,having from 3 to about 20 carbon atoms.

The combination of aliphatic and cyclic groups are groups comprising analiphatic portion and a cyclic portion, examples of which include, butare not limited to, groups such as: —(CH₂)_(m)C₆H_(q)R_(5-q) wherein mis an integer from 1 to about 10, and q is an integer from 1 to 5,inclusive; —(CH₂)_(m)C₆H_(q)R_(11-q) wherein m is an integer from 1 toabout 10, and q is an integer from 1 to 11, inclusive; or—(CH₂)_(m)C₅H_(q)R_(9-q) wherein m is an integer from 1 to about 10, andq is an integer from 1 to 9, inclusive.

Oxygen groups are oxygen-containing groups, examples of which include,but are not limited to, alkoxy or aryloxy groups (—OR), —OSiR₃, and thelike, wherein R in each instance is selected from alkyl, cycloalkyl, oraryl having from 1 to about 20 carbon atoms. Examples of alkoxy oraryloxy groups (—OR) groups include, but are not limited to, methoxy,ethoxy, propoxy, butoxy, phenoxy, substituted phenoxy, and the like.

Sulfur groups are sulfur-containing groups, examples of which include,but are not limited to, —SR, wherein R in each instance is selected fromalkyl, cycloalkyl, or aryl, having from 1 to about 20 carbon atoms.

Nitrogen groups are nitrogen-containing groups, which include, but arenot limited to, —NR₂, wherein R in each instance is selected from alkyl,cycloalkyl, or aryl, having from 1 to about 20 carbon atoms.

Phosphorus groups are phosphorus-containing groups, which include, butare not limited to, —PR₂, wherein R in each instance is selected fromalkyl, cycloalkyl, or aryl, having from 1 to about 20 carbon atoms.

Arsenic groups are arsenic-containing groups, which include, but are notlimited to, —AsR₂, wherein R in each instance is selected from alkyl,cycloalkyl, or aryl, having from 1 to about 20 carbon atoms.

Carbon groups are carbon-containing groups, which include, but are notlimited to, alkyl halide groups that include halide-substituted alkylgroups with 1 to about 20 carbon atoms, aralkyl groups with 1 to about20 carbon atoms, including alkyl, cycloalkyl, aryl, aralkyl, substitutedalkyl, substituted aryl, or substituted aralkyl groups.

Silicon groups are silicon-containing groups, which include, but are notlimited to, silyl groups such alkylsilyl groups, arylsilyl groups,arylalkylsilyl groups, siloxy groups, and the like, which in eachinstance have from 1 to about 20 carbon atoms. For example, silicongroups include trimethylsilyl and phenyloctylsilyl groups.

Germanium groups are germanium-containing groups, which include, but arenot limited to, germyl groups such alkylgermyl groups, arylgermylgroups, arylalkylgermyl groups, germyloxy groups, and the like, which ineach instance have from 1 to about 20 carbon atoms.

Tin groups are tin-containing groups, which include, but are not limitedto, stannyl groups such alkylstannyl groups, arylstannyl groups,arylalkylstannyl groups, stannoxy (or “stannyloxy”) groups, and thelike, which in each instance have from 1 to about 20 carbon atoms.

Boron groups are boron-containing groups, which include, but are notlimited to, —BR₂, wherein R in each instance is selected from alkyl,cycloalkyl, or aryl, having from 1 to about 20 carbon atoms.

Aluminum groups are aluminum-containing groups, which include, but arenot limited to, —AlR₂, wherein R in each instance is selected fromalkyl, cycloalkyl, or aryl, having from 1 to about 20 carbon atoms.

The present invention is further illustrated by the following examples,which are not to be construed in any way as imposing limitations uponthe scope thereof. On the contrary, it is to be clearly understood thatresort may be had to various other aspects, features, embodiments,modifications, and equivalents thereof which, after reading thedescription herein, may suggest themselves to one of ordinary skill inthe art without departing from the spirit of the present invention orthe scope of the appended claims.

EXAMPLES

Generally, the solvents used in the following Examples were dried anddistilled using standard methods. The Nuclear Magnetic Resonance (NMR)spectra reported herein were obtained on a Varian Mercury Plus 300 NMRspectrometer operating at 300 MHz for ¹H NMR (CDCl₃ solvent, referencedagainst the peak of residual CHCl₃ at 7.24 ppm) and 75 MHz for ¹³C NMR(CDCl₃ solvent, referenced against central line of CHCl₃ at 77.00 ppm).

Pentatriacontanone, ([CH₃(CH₂)₁₆]₂CO) was obtained from Alfa Aesar andwas used as received.

Cyclopentadienyl magnesium chloride (CpMgCl) was purchased from BoulderScientific as solution in THF. CpMgCl can also be prepared according tothe procedure detailed in U.S. Pat. No. 6,175,027. U.S. Pat. No.6,175,027 also provides a general description of cyclopentadienylGrignard synthesis methods. A method for preparing CpMgX is alsoreported by Stille and Grubbs in J. Org. Chem., (1989), 54, 441.Dicyclopentadienyl magnesium could be prepared according to Duff,Hitchcock, Lappert, and Taylor, J. Organometal. Chem. (1985), 293, 271.

Example 1 Preparation of 6,6-diheptadecylpentafulvene

Pentatriacontanone, ([CH₃(CH₂)₁₆]₂CO) 46.0 g (90.7 mmol), was slurriedin 100 mL of dry THF and stirred vigorously. A solution ofcyclopentadienylmagnesium chloride in THF, 125 mL (125 mmol), was addeddropwise. After about 30 minutes most of the ketone had dissolved.Stirring was continued for 2 hours and then the mixture was refluxed for2 hours. Stirring was further continued for about 16 hours, after whichtime the orange solution was cooled in an ice bath, and a mixture of 15mL of concentrated HCl(aq) and 100 mL of water was added. The resultingmixture was extracted with 200 mL of n-pentane and the organic layer waswashed with 3×100 mL of water and dried over sodium sulfate. Afterfiltration, the solvent was removed from the filtrate in vacuo toprovide a yellow paste. Both ¹H and ¹³C NMR spectra of this paste showedthe product to be a mixture of 6,6-diheptadecylpentafulvene and isomericalkenylcyclopentadienes, along with residual THF, 55.1 grams. The yieldof the alkenylcyclopentadienes was estimated from the ¹H NMR spectrum tobe about 51%. FIG. 1 illustrates the ¹H NMR spectrum of the crudereaction product arising from the reaction of CpMgCl and [CH₃(CH₂)₁₆]₂COin THF.

Example 2 Attempted Purification of 6,6-diheptadecylpentafulvene UsingChromatography

The mixture of 6,6-diheptadecylpentafulvene and isomericalkenylcyclo-pentadienes prepared according to Example 1 was dissolvedin 200 mL of n-pentane and passed through a short column (15 cm×4 cm) ofDavison Grade 62 silica. The resulting filtrate was concentrated undervacuum to provide a yellow solid. Both ¹H NMR and ¹³C NMR spectroscopyrevealed that the residual THF was removed, but the isomericalkenylcyclopentadienes were not removed. The yield of thealkenylcyclopentadienes was estimated from the ¹H NMR spectrum to beabout 54%, with 44.6 g of reaction product recovered. FIG. 2 illustratesthe ¹H NMR spectrum of the product arising from the reaction of CpMgCland [CH₃(CH₂)₁₆]₂CO in THF, following chromatography as described inthis example.

Example 3 Purification of 6,6-diheptadecylpentafulvene

A solution of 7.46 g (50 mmol) of 4-(N,N-dimethylamino)benzaldehyde and10 mL of pyrrolidine (120 mmol) in 50 mL of methanol and 70 mL ofmethylene chloride was degassed and added to 44.5 grams of crudediheptadecylpentafulvene. This mixture was stirred for about 20 h togive a dark red mixture. A 25 mL portion of glacial acetic acid in 100mL of water was added to this solution and the resulting mixture wasextracted with 200 mL of pentane. The organic layer was washed with3×100 mL of water, dried over magnesium sulfate, and filtered. Thesolvent was removed under vacuum leaving a viscous, dark red liquid. Aportion of this liquid, 27.8 g, was passed through a column of DavisonGrade 62 silica (30 cm×4 cm) and eluted with n-pentane. A yellow bandeluted first and was well separated from a dark red band. The yellowsolution collected first was concentrated under vacuum to provide ayellow oil, 8.5 g. Both ¹H NMR and ¹³C NMR spectra of this oil indicatedthe oil was pure 6,6-diheptadecylpentafulvene. Chromatography of asecond batch of dark red liquid according to the above techniqueprovided more pure 6,6-diheptadecylpentafulvene and brought the totalyield to 14.2 g. FIG. 3 illustrates the ¹H NMR spectrum of the pure6,6-diheptadecylpentafulvene product.

Throughout this disclosure, unless otherwise stated, any recitation of arange or a number is inclusive of the end members of that range. Forexample, the recitation that an alcohol has up to 4 carbon atoms isintended to refer to an alcohol having 1, 2, 3, or 4 carbon atoms.Further, unless otherwise stated, the recitation that n is an integerfrom 6 to 16 is intended to include the end members 6 and 16 in thepossible values for integer n.

Although any methods, devices, and materials similar to or equivalent tothose described herein can be used in the practice or testing of theinvention, the typical methods, devices and materials are hereindescribed.

All publications and patents mentioned in this disclosure areincorporated herein by reference in their entireties, for the purpose ofdescribing and disclosing, for example, the constructs and methodologiesthat are described in the publications, which might be used inconnection with the presently described invention. The publicationsdiscussed above and throughout the text are provided solely for theirdisclosure prior to the filing date of the present application. Nothingherein is to be construed as an admission that the inventors are notentitled to antedate such disclosure by virtue of prior invention.

To the extent that any definition or usage provided by any documentincorporated herein by reference conflicts with the definition or usageprovided herein, the definition or usage provided herein controls.

For any particular compound disclosed herein, any general structurepresented also encompasses all conformational isomers, regioisomers, andstereoisomers that may arise from a particular set of substituents. Thegeneral structure also encompasses all enantiomers, diastereomers, andother optical isomers whether in enantiomeric or racemic forms, as wellas mixtures of stereoisomers, as the context requires.

1. A method of isolating a fulvene from a composition comprising thefulvene and at least one cyclopentadiene-containing impurity,comprising: a) contacting the composition with4-(N,N-dimethylamino)benzaldehyde, pyrrolidine, and optionally a firstsolvent to provide a first mixture; b) contacting the first mixture withan aqueous acid to provide a second mixture; c) extracting the secondmixture with a second solvent to provide an extract, optionallyconcentrating the extract, and optionally drying the extract; and d)isolating the fulvene from the extract by chromatography; wherein:

the fulvene has the formula R¹, R², and R³, in each occurrence, areindependently a hydrocarbyl group having up to 20 carbon atoms, orhydrogen.
 2. The method according to claim 1, wherein R¹ and R² areselected independently from: a) a linear or a branched alkyl group; b) alinear or a branched alkenyl group; c) an aryl group; or d) anaryl-substituted linear or branched alkyl group; any of which having upto 20 carbon atoms.
 3. The method according to claim 1, wherein R³, ineach occurrence, is selected independently from: a) a linear or abranched alkyl group having up to 12 carbon atoms; or b) hydrogen. 4.The method according to claim 1, wherein R¹ and R² are, independently,an alkyl group having from 1 to 18 carbon atoms.
 5. The method accordingto claim 1, wherein the fulvene has the formula:

R³, in each occurrence, is independently a linear or a branched alkylgroup having up to 6 carbon atoms; m is 0, 1, 2, 3, or 4; and n is aninteger from 1 to
 16. 6. The method according to claim 1, wherein thefulvene has the formula:

R³, in each occurrence, is independently a linear or a branched alkylgroup having up to 6 carbon atoms; m is 0, 1, 2, 3, or 4; and n is aninteger from 6 to
 16. 7. The method according to claim 1, wherein the atleast one cyclopentadiene-containing impurity is

or a combination thereof, wherein n is an integer from 1 to
 16. 8. Themethod according to claim 1, wherein the at least onecyclopentadiene-containing impurity is

or a combination thereof, wherein n is an integer from 6 to
 16. 9. Themethod according to claim 1, wherein the fulvene has the formulaC₄H₄C═C(CH₂)₁₆CH₃.
 10. The method according to claim 1, wherein thefirst solvent is a mixture of methylene chloride and an alcohol havingup to 4 carbon atoms.
 11. The method according to claim 1, wherein thefirst solvent is a mixture of methylene chloride and methanol.
 12. Themethod according to claim 1, wherein the second solvent is pentane,hexane, heptane, or any combination thereof.
 13. The method according toclaim 1, wherein the aqueous acid is acetic acid, trifluoroacetic acid,formic acid, hydrochloric acid, phosphoric acid, sulfuric acid, nitricacid, or any combination thereof.
 14. The method according to claim 1,wherein the extract is concentrated prior to isolating the fulvene fromthe extract by chromatography.
 15. The method according to claim 1,wherein the extract is dried prior to isolating the fulvene from theextract by chromatography.
 16. A method of isolating a fulvene from acomposition comprising the fulvene and at least onecyclopentadiene-containing impurity, comprising: a) contacting thecomposition with 4-(N,N-dimethylamino)benzaldehyde, pyrrolidine, andoptionally a first solvent to provide a first mixture; b) contacting thefirst mixture with an aqueous acid to provide a second mixture; c)extracting the second mixture with a second solvent to provide anextract, optionally concentrating the extract, and optionally drying theextract; and d) isolating the fulvene from the extract bychromatography; wherein: the fulvene has the formulaC₄H₄C═C[(CH₂)₁₆CH₃]₂.
 17. The method according to claim 16, wherein thefirst solvent is a mixture of methylene chloride and an alcohol havingup to 4 carbon atoms.
 18. The method according to claim 16, wherein thefirst solvent is a mixture of methylene chloride and methanol.
 19. Themethod according to claim 16, wherein the second solvent is pentane,hexane, heptane, or any combination thereof.
 20. The method according toclaim 16, wherein the aqueous acid is acetic acid, trifluoroacetic acid,formic acid, hydrochloric acid, phosphoric acid, sulfuric acid, nitricacid, or any combination thereof.
 21. The method according to claim 16,wherein the extract is concentrated prior to isolating the fulvene fromthe extract by chromatography.
 22. The method according to claim 16,wherein the extract is dried prior to isolating the fulvene from theextract by chromatography.